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United States Patent |
6,004,081
|
Hellstrom
,   et al.
|
December 21, 1999
|
Tool for metal cutting
Abstract
A tool for cutting metal machining comprises one or several cutting insert
seats (1), each one for an indexable cutting insert, each insert seat
comprising a bottom support surface (10) and at least two side surfaces,
which form a right angle with each other. One of these side surfaces
comprises two side surfaces (12, 16), which are located at different
distances from the bottom support surface (10), one of these being
intended as a support surface for square cutting inserts and the other as
a support surface for specially shaped hexagonal inserts. In this way, one
and the same insert seat can accommodate either a square or a hexagonal
cutting insert, which considerably improves cutting economy.
Inventors:
|
Hellstrom; Lars (.ANG.rsunda, SE);
Roman; Stefan (Sandviken, SE);
Pantzar; Goran (.ANG.rsunda, SE);
Kemper; Erwin (Mulheim-Ruhr, DE);
Scherbarth; Stefan (Neuss, DE)
|
Assignee:
|
Sandvik AB (SE)
|
Appl. No.:
|
983038 |
Filed:
|
March 27, 1998 |
PCT Filed:
|
July 11, 1996
|
PCT NO:
|
PCT/SE96/00938
|
371 Date:
|
March 27, 1998
|
102(e) Date:
|
March 27, 1998
|
PCT PUB.NO.:
|
WO97/03779 |
PCT PUB. Date:
|
February 6, 1997 |
Foreign Application Priority Data
| Jul 18, 1995[SE] | 9502645 |
| Dec 29, 1995[SE] | 9504688 |
Current U.S. Class: |
407/103; 407/101; 407/102 |
Intern'l Class: |
B23B 027/16 |
Field of Search: |
407/113,101-103,34,53,47
|
References Cited
U.S. Patent Documents
1838520 | Dec., 1931 | Archer.
| |
3268977 | Aug., 1966 | Diemond | 407/103.
|
4600341 | Jul., 1986 | Board.
| |
4616962 | Oct., 1986 | Ushihima et al. | 407/113.
|
4966500 | Oct., 1990 | Tsujimura et al.
| |
5123787 | Jun., 1992 | Hunt.
| |
5145294 | Sep., 1992 | Flueckiger.
| |
5382118 | Jan., 1995 | Satran et al. | 407/42.
|
5827016 | Oct., 1998 | Strand | 407/113.
|
Foreign Patent Documents |
34 25 012A1 | Jan., 1985 | DE.
| |
323 566 | May., 1970 | SE.
| |
Primary Examiner: Howell; Daniel W.
Assistant Examiner: Williams; Mark
Attorney, Agent or Firm: Burns, Doane, Swecker & Mathis, L.L.P.
Claims
We claim:
1. Tool for cutting metal machining comprising at least one cutting insert
seat for accommodating at least one indexable cutting insert, the at least
one insert seat including a bottom support surface and at least two side
surfaces, the at least two side surfaces forming a substantially right
angle with each other and include support surfaces adapted to bear against
the cutting insert mounted in the insert seat, one of the at least two
side surfaces including at least two support surfaces, the at least two
support surfaces being located at different distances from a plane of the
bottom support surface, one of the at least two support surfaces being
shaped to support cutting inserts of a substantially square basic shape
and another of the at least two support surfaces being shaped to support
cutting inserts of a substantially hexagonal basic shape.
2. Tool according to claim 1, wherein another side surface of the at least
two side surfaces has at least one support surface being shaped to support
both cutting inserts of a substantially square basic shape and cutting
inserts of a substantially hexagonal basic shape.
3. Tool according to claim 1, wherein at least the support surface for the
insert of a substantially square basic shape is divided into two part
support surfaces by a recess.
4. Tool according to claim 1, wherein the at least two support surfaces on
one of the at least two side surfaces are substantially plane-parallel.
5. Tool according to claim 1, wherein the support surface for the insert of
a substantially hexagonal basic shape is divided into two part support
surfaces by a recess.
6. Tool according to claim 1, wherein the support surface for the insert of
a substantially square basic shape is divided into two part support
surfaces by a recess, the recess also dividing the support surface for the
insert of a substantially hexagonal basic shape into two part support
surfaces.
7. Tool according to claim 1, wherein the at least two support surfaces on
one of the at least two side surfaces are substantially plane-parallel,
the support surface for the insert of substantially hexagonal basic shape
being located at a larger distance from a middle point of the bottom
support surface than the support surface for the insert of a substantially
square basic shape.
8. Tool for cutting metal machining comprising at least one cutting insert
seat for accommodating at least one indexable cutting insert, the at least
one insert seat including a bottom support surface and at least two side
surfaces the at least two side surfaces forming a substantially right
angle with each other and include support surfaces which are adapted to
bear against the cutting insert mounted in the insert seat, the at least
two side surfaces each including at least two support surfaces located at
different distances from a plane of the bottom support surface of the at
least two support surfaces being shaped to support cutting inserts of a
substantially square basic shape and another support surface of the at
least two support surfaces being shaped to support cutting inserts of a
substantially hexagonal basic shape.
9. Tool according to claim 8, wherein the support surface for the insert of
a substantially square basic shape is divided into two part support
surfaces by a recess.
10. Indexable cutting insert of a substantially hexagonal basic shape for
cutting metal machining comprising a bottom surface, a top or chip
surface, and a configuration of side surfaces extending therebetween, the
configuration of side surfaces including at least six first abutment
surfaces, each abutment surface of the at least six first abutment
surfaces being located proximate a main cutting edge, and the
configuration of side surfaces including at least six second abutment
surfaces located proximate an intersection line of the configuration of
side surfaces with the bottom surface.
11. Indexable cutting insert according to claim 10, wherein the
intersection line between the bottom surface and the configuration of side
surfaces describes a dodecagon.
12. Indexable cutting insert according to claim 10, wherein a center of
each first abutment surface of the at least six first abutment surfaces is
disposed substantially midway between two succeeding second abutment
surfaces of the at least six second abutment surfaces.
13. Indexable cutting insert of a substantially hexagonal basic shape for
cutting metal machining comprising a bottom surface, a top or chip
surface, and a configuration of side surfaces extending therebetween, the
configuration of side surfaces including at least six first abutment
surfaces, each abutment surface of the at least six first abutment
surfaces being located proximate a main cutting edge, and the
configuration of side surfaces including at least six second abutment
surfaces located proximate an intersection line of the configuration of
side surfaces with the bottom surface wherein each first abutment surface
of the at least six first abutment surfaces forms part of a corresponding
first surface portion of a plurality of first surface portions, and each
second abutment surface of the second abutment surfaces forms part of a
corresponding second intermediate surface portion of a plurality of
corresponding second intermediate surface portions, each intermediate
surface portion of the plurality of second intermediate surface portions
being located between two of the first surface portions.
14. Indexable cutting insert according to claim 13, wherein a land is
disposed between two first abutment surfaces of the at least six first
abutment surfaces and a second intermediate surface portion of the
plurality of second intermediate surface portions.
15. Indexable cutting insert according to claim 13, wherein the first
surface portions include a waist portion having a convex radius, and that
a second intermediate surface portion has a concave radius.
16. Indexable cutting insert according to claim 15, wherein the second
intermediate surface portion has a substantially hexagonal basic shape,
the concave radius extending between two opposed corners of the hexagonal
basic shape.
17. Indexable cutting insert of a substantially hexagonal basic shape for
cutting metal machining comprising a bottom surface, a top or chip
surfaces, and a configuration of side surfaces extending therebetween, the
configuration of side surfaces including at least six abutment surfaces,
each abutment surface of the at least six abutment surfaces being located
proximate a main cutting edge, and at least six other surfaces which are
unground and are disposed proximate an intersection line of the
configuration of side surfaces with the bottom surface.
18. Indexable cutting insert according to claim 17, wherein, underneath
each abutment surface, a transition surface is disposed and is angled
downwards-inwards toward a center of the cutting insert, and wherein,
below the transition surface, a free-surface extending to the bottom
surface of the cutting insert is disposed.
19. Indexable cutting insert according to claim 17, wherein each abutment
surface of the at least six abutment surfaces forms part of a first
surface portion of a plurality of first surface portions, and that each
other surface of the at least six other surfaces forms part of a second
intermediate surface portion, each second intermediate surface portion
being located between two first surface portions of the plurality of first
surface portions.
20. Indexable cutting insert according to claim 17, wherein the
intersection line between the bottom surface and the configuration of side
surfaces describes a substantially regular hexagon with rounded corners.
21. Indexable cutting insert according to claim 17, wherein a land is
disposed between two abutment surfaces of the at least six abutment
surfaces.
Description
The present invention relates to a tool for cutting metal machining
according to the preamble of claim 1. More specifically, the invention
relates to a tool that makes possible a fastening of indexable cutting
inserts with different numbers of cutting edges in one and the same insert
seat.
The use of detachable, indexable cutting inserts is nowadays common
practice for generally all cutting metal machining, i.e. for turning,
milling, boring, etc. They are usually made of coated or uncoated cemented
carbide, but some ceramic materials also occur. These different indexable
cutting inserts may have very varying geometrical basic shapes, depending
upon cutting economy and applications. They may e.g. be triangular,
rhombic, square, rectangular, round, hexagonal and octagonal. Further,
they may be double-sided or single-sided, depending on if cutting edges
are present on both sides or only one side.
Common for all possible different insert shapes is that they require an
insert seat in the holder per se adapted to the shape of the insert. Thus,
square inserts normally require an insert seat with two mutually
perpendicular support or bearing surfaces in the insert seat, a round
insert requires a round support surface, or at least segments of such a
surface, an insert with the shape of a regular hexagon necessitates two
support surfaces that are angled by 120.degree. to each other (or two
surfaces at a distance that are angled by 60.degree. to each other), etc.
This means that a change of insert shape also requires a change of
holders. This is time-consuming and, primarily, expensive.
The advantage with, e.g., a hexagonal insert in comparison with a square
one, is of course that the hexagonal one has more cutting edges, more
precisely for a single-sided insert, two more. Naturally, this involves a
better cutting economy, since by one and the same insert, one in principle
may extend the working time by 50%. However, some disadvantages with
hexagonal cutting inserts is that they do not make possible the same
cutting depth as for instance square inserts do (i.e., inserts with the
same extension from the middle point to the operative cutting corner), and
that they do not make possible 90.degree. milling or turning. Therefore,
it is desirable or necessary to sometimes replace for instance square
cutting inserts, whereby also the holder has to be replaced, as mentioned
above.
For instance, in U.S. Pat. No. 4,966,500 holders are disclosed for
different basic shapes of cutting inserts, such as square, hexagonal and
octagonal. It may easily be understood that square and octagonal inserts
could be fitted into the same insert seats, since both these have cutting
edges located perpendicularly to each other. However, hexagonal inserts
require their own holders, which may be seen in that citation.
Thus, a first object of the present invention is to improve the cutting
economy by optimizing the number of cutting edges in one and the same
holder.
A second object of the present invention is to provide an insert seat that
may accommodate both square and hexagonal inserts.
Another object of the present invention is to provide a hexagonal insert
that may fit in an insert seat for square inserts.
These and further objects have been achieved in a way that is surprising
for the skilled man, by constructing a cutting insert seat and a cutting
insert, respectively, with the features as defined in the claims 1 and 5.
For illustrative but non-limiting purposes, some preferred embodiments of
the invention will now be further described with reference to the appended
drawings.
These are herewith briefly presented:
FIG. 1 shows an exploded view of an insert seat according to the invention,
in a perspective obliquely from above.
FIG. 2 shows an exploded view of a somewhat modified insert seat according
to the invention, in perspective obliquely from above.
FIG. 3 shows the same insert seat as FIG. 1, but with a hexagonal insert
instead of a square one.
FIG. 4 shows the corresponding insert and insert seat as FIG. 3, however
without a shim.
FIG. 5 shows the bottom side of a hexagonal insert according to the
invention, in a perspective obliquely from above.
FIG. 6 shows the same insert seat as FIG. 2, but with a hexagonal insert
instead of a square one.
FIG. 7 shows the corresponding insert and insert seat as FIG. 6, however
without a shim.
FIG. 8 shows the bottom side of another embodiment of a hexagonal insert
according to the invention, in a perspective obliquely from above.
FIG. 9 shows a milling cutter body with cutting insert seats according to
the invention according to FIG. 1, a square and a hexagonal insert having
been mounted.
FIG. 10 shows a milling cutter body with insert seats according to the
invention according to FIG. 2, a square and a hexagonal insert having been
mounted.
In FIG. 1 a cutting insert seat according to the invention is generally
designated by reference numeral 1. As may be seen in FIG. 9, this insert
seat is located in a milling cutter body 2, but in principle it may also
be placed in, e.g., a boring bar or a drill tip. Basically, the cutting
insert seat consists of a bottom support surface 10 and two side surfaces
40 and 41, which are substantially perpendicular to each other. In this
insert seat is mounted an indexable cutting insert 3, which according to
FIG. 1 has a square basic shape. In order to protect the milling cutter
body against any possible insert breakdown, the insert 3 rests upon a shim
4, which normally is also made of cemented carbide. The shim is fastened
in the insert seat 1 by an internally and externally threaded shim screw
5, which is tightened into the threaded hole 6 of the insert seat by means
of a hexagon key that fits into the hexagonal hole 7. Thereby, the bottom
surface of the shim will bear against the bottom support surface 10 of the
insert seat. Moreover, the shim bears against the side support surface 14;
on the other hand, it usually does not reach the other, lower side surface
of the insert seat, in this case the rounded surface 13. According to the
exemplified embodiment, the surface 14 consists of a planar surface and
the surface 13 of a boring with a sector-shaped cross-section. The central
hole of the shim is formed with an abutment shoulder 8, against which the
underside of the head of the shim screw 5 abuts. The locking screw 9 is
threaded into the inner thread of the shim screw 5 and, thereby, it locks
the insert 3, the bottom side of the insert pressing against the top
surface of the shim. The head of the locking screw 9 is provided with a
recess for tightening, e.g., a so called torx recess 37. When the
indexable cutting insert 3 is fastened in the insert seat 1, it will bear
against the axial support or abutment surface 11 and the radial support or
abutment surfaces 12A and 12B, respectively, which latter two are located
in the same plane. All these are angled to the bottom surface 10 by
substantially the same angle as the side or relief surfaces 52 of the
insert are angled to the bottom surface of the insert. Thus, the angle
between said abutment surfaces and the normal of the bottom support
surface is between 3 and 30.degree.. Between the cutting edges that are
turned inwards and non-operative, and the surfaces above the abutment
surfaces 11, 12, is a gap, so that these cutting edges are not damaged.
These two gaps 42 and 43 may be seen in FIG. 9.
In FIG. 3 the same insert seat is illustrated as in FIG. 1, but with a
hexagonal insert 15 mounted instead of the square insert 3. Thus, the
other included machine elements are identical. When this insert is
fastened in the insert seat, it will abut on one hand against the axial
abutment surface 11, thus against the same surface as the square insert in
FIG. 1 abuts against, and on the other hand against the support or
abutment surfaces 16A and 16B, which are located in one and the same
plane. This plane is substantially plane-parallel to the plane of abutment
surfaces 12A, 12B and located somewhat farther away from the axis of the
center hole 6, than the latter plane. Between on one hand the surfaces
12A, 12B, and on the other hand the surfaces 16A, 16B, is provided a
transition shoulder 39. The surfaces 12A, 12B and 16A, 16B, respectively,
are separated from each other by means of a substantially straight
milled-out recess 17. This recess need not per se intersect the surface
16, but nevertheless it contributes favourably to providing a statically
well-defined two-point abutment radially.
In order to make a cutting insert with the shape of a regular hexagon fit
into the insert seat, it should be shaped so that it comprises the
features as shown in FIG. 5. The bottom side of the insert has the shape
of a dodecagon, and it may be brought to be regular, but preferably it is
defined by alternating somewhat shorter and somewhat longer edges 19A and
19B, respectively.
According to the embodiment shown in FIG. 5, the side surfaces 15 of the
insert, which hence extend between the bottom surface 18 and the top
surface or chip surface, are shaped in a way that will now be described
further. From each part edge 19A starts a surface portion 20, which first
forms a tapering portion 23, that tapers substantially in the form of a
trapezoid or an isosceles frusto-triangle, into a narrower waist portion
21, and then it widens again in the direction of the chip surface, whereby
it forms an abutment surface 22, which is intended to bear against the
abutment surface 16A, 16B. The intersection line between the abutment
surface 22 and the top side of the insert form a main cutting edge 30. It
should be pointed out that the part of the abutment surface 22 situated
adjacent the main cutting edge 30 does suitably not come in contact with
the support surfaces 16, in order not to damage said edge when it has been
indexed inwardly in the insert seat. Thus, as may be seen in FIG. 9, the
six-edge insert 15 protrudes from the upper delimiting lines of the insert
seat (i.e., the upper delimitation line of the support surfaces 16).
Suitably, the surface 20 is somewhat convexly curved at the waist portion
21, which may be seen left-most in FIG. 4. Thereby the main cutting edge
30 is strengthened on the relief side, in order to withstand larger
cutting forces. If this would not be considered necessary, the knick point
at the waist portion could be deleted, whereby the whole "spatulate"
surface 20 is in one single plane. For small cutting forces, even an
inversion of the waist portion would be feasible, i.e., the waist portion
21 would exhibit a concave radius, corresponding to the radii 25 described
below.
Between the surface portions 20, the cutting insert has intermediate
portions 24, which have a hexagonal basic shape that is curved
substantially along the connection line between two opposed corners. This
curving forms a concave radius surface 25. That part of the intermediate
portion 24 that adjoins a part-edge 19B constitutes an abutment surface
26, which may be brought to bear against the axial support surface 11.
However, suitably, the whole abutment surface 26 is not intended to bear
against the support surface 11. More specifically, the part of the surface
26 situated adjacent the edge 19B will not cooperate with said support
surface, but rather the part located nearer the radius surface 25. The
transition surface 27 protruding from the center of the insert constitutes
a free-surface, whose width decreases from the radius surface 25 in the
direction of the chip surface of the insert. Between this transition
surface and the chip surface there is a parallel land 28, whose secondary
land cutting edge 29 generates a smooth surface on the workpiece, in a
manner known per se. In the transitional region between the appurtenant
abutment surface 22 and the parallel land 28, there is preferably a
transition surface 31, which either is planar or has a radius. Further,
this surface 31 is somewhat more inclined in relation to the normal of the
bottom surface than is the abutment surface 22, in this way allowing for a
sufficient clearance behind the cutting edge of the parallel land
(axially).
A characteristic, combinatory double effect of the present invention is
realized by the existence of on one hand the recess or milled-out recess
17 in the one support surface of the insert seat, and on the other hand
the "spatulate" surface portion 20 on the hexagonal cutting insert 15. By
shaping the former sufficiently broad and the latter sufficiently narrow
at the waist portion 21, said waist portion may be fitted into and go free
from the recess 17, and thus be countersunk between the support surface
portions 12A, 12B. Thereby, the feature characteristic for the present
invention is achieved, that support surfaces on different levels may be
used for different insert shapes.
Above the axial support surface 11 there is an elongated intermediate
surface 36, which is located substantially on the same height from the
bottom support surface 10 as the support surfaces 16A, 16B. This
intermediate surface 36 is to be considered as a mere free-surface,
without any contact to a mounted cutting insert.
In FIGS. 1 and 3 (and also in FIGS. 2 and 6) embodiments are illustrated
comprising a shim 4. However, this is not an essential feature of the
present invention, which also comprises constructions without such a shim.
Such a one is shown in FIG. 4. The only difference between this figure and
FIG. 1 and 3 is that the bottom support surface 10 protrudes by a height
difference corresponding to the thickness of the shim. This brings about
the advantage per se that the material thickness in the insert-carrying
protrusion 32 becomes thicker and, thereby, stronger.
As may be best seen in FIG. 1, one or several of the support surfaces 11,
12 and 16 may be provided with sparing surfaces 33, 34 and 35,
respectively. These are arranged so that the side edges shall not be
capable of causing intrusions in the insert seat, thereby damaging it in
the long run.
FIG. 9 shows a milling cutter body with six identical cutting insert seats,
which are shaped to correspond the embodiment according to FIG. 1 and 3.
In the figure, two of these are equipped, one with an indexable cutting
insert of a square basic shape and one with an indexable cutting insert of
a hexagonal basic shape. However, this is not a combination that is used
for a real machining step, but is to be seen as a mere illustration of the
basic concept of the present invention.
According to the illustrated embodiments, the support surface 11, that is
common for the two insert types, is the axial support surface. However, it
may easily be realized that the locations of the side surfaces may be
converted, whereby the support surface 11 would become the radial support
surface and the support surfaces 12 and 16 axial support surfaces.
FIG. 2 and the appurtenant FIGS. 6, 7, 8 and 10 show an embodiment of the
invention that is somewhat modified relative to FIG. 1. Corresponding
details have been designated with the same reference numerals as in the
corresponding FIGS. 1, 3, 4, 5 and 9. One difference between FIG. 9 and 10
is that in FIG. 10 only one cutting-edge-protecting gap (gap 42) exists,
which is located between one of the non-active cutting edges of the
insert, being directed inwardly, and the surface above the abutment
surfaces 12.
In FIG. 6 is illustrated the same insert seat as in FIG. 2, but with a
hexagonal cutting insert 15' mounted, instead of the square insert 3.
Thus, the other included machine elements are identical. When this cutting
insert is fastened in the insert seat, it will bear on one hand against
the axial abutment surface 43, and on the other hand against the support
or abutment surface 16. The plane of the surface 16 may be substantially
plane-parallel with the planes of the abutment surfaces 12A, 12B and
located somewhat farther from the axis of the center hole 6, than the
latter plane. The angle of the plane 16 to the normal of the bottom
surface 10 can be somewhat smaller than the angle of the corresponding
abutment surface 22 on the insert, which in principle permits a linear
abutment between the cutting insert and the upper delimitation line of the
abutment surface 16. The level of said delimitation is determined by the
formation of the milled-out free-surface 49.
In order to make a cutting insert of a regular hexagonal shape fit into
this insert seat, it shall be formed so that it comprises the features as
depicted in FIG. 5 or 8. The cutting insert according to FIG. 5 has
already been described above. However, by the somewhat modified insert
seat according to FIG. 2, it will rest in a somewhat different way, as
described below.
In combination with FIG. 2, the surfaces 22 are intended to abut on one
hand against the abutment surface 16 (or against its upper delimitation
line) and on the other hand against the abutment surface 43, which are
angled substantially by 120.degree. to each other. As mentioned above, the
part of the abutment surface 22 located adjacent the main cutting edge 30
should not come in contact with the support surface 16, in order not to
damage said cutting edge when it has been indexed inwardly into the insert
seat. Of the same reason, there is preferably a free-surface 44 above the
abutment surface 43. However, the surface 44 is not necessary, cf. FIG. 7.
According to FIG. 1, that part of the intermediate portion 24 that adjoins
a part-edge 19B constitutes an abutment surface 26, which is brought to
abut against the same axial abutment surface as the square cutting insert.
Admittedly, this brings the inconvenience that the insert has to be ground
considerably, since abutment surfaces usually have to be ground. According
to FIG. 2, only the circumferential, cutting-edge-adjacent surfaces 22
function as abutment surfaces, which makes the insert considerably more
easily ground.
The cutting insert according to FIG. 8, whose bottom surface has the shape
of a substantially regular hexagon with rounded corners, is described
below.
According to FIG. 8, the spatulate surface 20 has been replaced by an
abutment surface 22', a transition surface or free-surface 50 that is
angled inwardly towards the center of the insert, and a free-surface 23'
extending between surface 50 and the bottom surface of the insert. The
bottom surface 18' has the shape of a regular hexagon with rounded
corners. Between two adjacent free-surfaces 23', there are provided
rounded radius surfaces 51, which in principle replace the intermediate
portions 24 in FIG. 5. The parallel lands 28' and the transition surfaces
31 ' correspond to details 28 and 31, respectively, in FIG. 5. According
to this embodiment, the transition surfaces 50 are considerably angled
towards the center of the insert, so that they, and also the free-surfaces
23', do not come in contact with the facing surfaces in the insert seat,
in first hand the surfaces 12 and 14, and 11, 15 and 46, respectively.
Also this embodiment has the endeavoured feature, that all side abutment
surfaces of the insert (i.e., the surfaces 22') are located at the top,
along the cutting edges, which makes the cutting insert easy to grind.
Between the axial support surface 11 for square inserts and the round
surface 13, there is a free-surface 45. At the opposed side of the support
surface 11, there is arranged a transition surface 46, which is
substantially plane-parallel with the bottom supports surface 10. Between
this one and the support surface 43 for hexagonal inserts, extends another
transition surface 47, which forms an obtuse angle relative to both
surfaces 43 and 46. Adjacent to the surfaces 43, 44 and at the same
distance as those from the bottom support surface 10, there is a
free-surface 48. As may be easily understood, the hexagonal insert
according to FIG. 8 and the insert seat are mutually so shaped, that the
insert goes free from all surfaces below the support surface 43, i.e.
surfaces 13, 45, 11, 46 and 47, and of course also from the laterally
arranged surface 48.
Furthermore, according to the illustrated embodiments the indexable cutting
inserts have been provided with a through central hole 38 for the
fastening by a locking screw. However, this has nothing to do with the
ingenious location of the support surfaces in the insert seat, wherefore
also other clamping arrangements are feasible, such as a center pin or a
lever pin, and also such constructions that do not require any central
hole in the insert, e.g. a wedge or a pressing clamp.
Top